Protective device



Sept. 1, 1931. w. A. SMITH PROTECTIVE DEVICE Filed May 5, 192a INVENTOR.mlliamflfimi f1: BY

I H15 ATTORNEY Patented Sept. 1 1931 COMPANY, OF JERSEY CITY, NEWJERSEY, A CORBORATION OF NEW JERSEY.

PROTECTIVE :onvion Application filed May 5,

This invention relates to rock drills of the hammer type, but moreparticularly to a proteclive device adapted to be inserted in theforward closure of the cylinder, as for ginstance the lubricator, to actas aguiding surface for the piston extension.

One object of the invention is to protect the lubricator or itsequivalent against wear caused by the action of the piston extension.

Other objecLs will'be in part obvious and in part pointed outhereinafter.

In the drawings accompanying the specification and in which similarreference character refer to similar parts,

Figure l is a longitudinal elevation partly in secion of a rock. drillillustrating a practical application of the invention, and

Figure 2 is a transverse View taken through Figure 1 on the line 2-2looking in if the direcion indicated by the arrows.

Referring to the drawings, A represents the cylinder of a rock drill andB a back head which may be secured to the cylinder by means of sidebolts C.

The cylinder A has a free exhaust port D which is controlled by a pistonE reciprocable in the cylinder. The piston Emay be of a well known typehaving ahead F and a reduced extension G which extends into a chuck Hfor delivering blows of impact to a workin implement J, only the shank Kof which is indicated in the drawings.

A. closure is provided for the front end of die cylinder in the form ofa lubricator L comprising a body portion 0 having a bore I through whichextends the extension G. The front end of thebody portion 0 carries asleeve Q, the interior of which forms a bearing surface for the chuck H,and a flange R at the forward end of the sleeve Q lies be ween the frontend of the cylinder A and the rearward end of a front head S for holdingthe lubricator L against endwise movement in the cylinder A. In theperiphery of the lubricator L is an annular chamber T for the receptionof lubricant intended to lubricate the movable elements of the drillforwardly of the lubricator, such as the chuck parts. v 7

In accordance with the present invention 1923. Serial no. 275,343.

WILLIAM a. SMITH. o rnrnnrrsauna, new ASSIGNOR To IneEnsoLLsaANnthebo're P in the lubricator L through which:

the piston exiension G extends is of consid-{ erably larger diameterthan the piston ex tensionand comprises a reduced-portion U and arearward enlarged portion V5 "With in the reducedportion U is disposed abushing W the bore X of which forms a guiding surface for the pisionextension G. At the rearward end of the bushing IN is a lateral flange Ywhich lies in the enlarged portion V of the bore P and is of a thicknesssubstantially equal to the depth of the enlarged portion. V of the boreso that the rearward end of the flange will lie flush with or slightlybelow the corresponding end of the lubricator L.

In the periphery of the flange Y is a notch Z which registerswith a holeZ) in the I I less length than that of thehole so that normally the-rewill beonly a very slight endwise movement of the pin 0. Such movementof the pin however, is not objectionable since the'lubricator L at alltimes remains stationary with respect to the cylinder, the wall of whichserves to retain the pin 0 inthe hole 6.

Heretofore in drills of this type it has been the usual practice to usethe bore P in the lubricator as a guiding surface for the pistonextension G. After a certain period of usage the action of the pistonextension G caused such wear in the body portion 0 of the lubricator asto necessitate the replacement of the riod of time that would berequired to replace the lubricator and at a very much smaller expense.

I claim: 5 In a, rock drill, the combination of a cylinder and a piston,an extension on the piston, a lubricator forming a closure for the frontend of the cylinder, said lubricator having a bore comprising a reducedportion and an en 10 larged portion, a bushing in the reduced portionforming a guide for the extension, a flange 0n the bushing lying in theenlarged portion of the bore, said flange having a notch in itsperiphery, a hole in the lubricator 1 registering with said notch, and apin in the hole engaging said notch for locking the bushing in thelubricator, said pin being retained in the hole by the cylinder.

Intestiinony whereof I have signed this 20. specification.

7 WILLIAM A. SMITH.

